Redundant power supplies are becoming more popular. For example, 1+1 or N+1 redundant power supplies for electronic equipment, such as servers and/or telecommunication equipment are becoming more prevalent. A redundant power supply configuration can include two or more power supply configurations. Redundant power supplies can assist in ensuring that the associated electronic equipment can continue to operate if one or more of the power supplies is or becomes unavailable. However, if an Oring-FET of a redundant power supply configuration is faulty, voltage on a system bus in the electronic equipment can be low or sag causing the electronic equipment to experience an undesirable reboot.
Referring to FIG. 1, a simplified block diagram of a basic N+1 redundant power supply configuration in accordance with an exemplary embodiment is illustrated. In FIG. 1, the N+1 redundant power supply configuration 100 comprises three power supply configurations. Each redundant power supply configuration can include a power supply 102, an Oring-FET 104 and an Oring-FET controller 106. The power supply 102 can be communicatively coupled to an Oring-FET 104 with the power supply 102 providing power to the Oring-FET 104. The Oring-FET 104 can isolate the power supply 102 from a communicatively coupled system bus 108. The Oring-FET 104 can serve as a diode to prevent reverse current flowing towards the power supply 102 when the Oring-FET 104 is operating properly. An Oring-FET controller 106 can be communicatively coupled to the Oring-FET 104. The Oring-FET controller 106 can control the communicatively coupled Oring-FET 104 when the Oring-FET 104 is operating properly. In the event that the Oring-FET 104 is faulty, the Oring-FET 104 acts as a short. A shorted Oring-FET 104 can cause a low voltage or voltage sag on the communicatively coupled system bus 108 when the power supply 102 is plugged into the system. In the event, a sufficient voltage sagging of the system bus 108 occurs, the voltage sag can cause an undesirable system reboot.
Referring to FIG. 2, a detailed block diagram of a power supply configuration for a redundant power supply configuration in accordance with an exemplary embodiment is illustrated. As shown, the power supply configuration 200 can include an alternating current (AC) or direct current (DC) power supply 202 which can provide power to an electromagnetic compatibility (EMC) filter 204. The EMC filter 204 can reduce and/or eliminate electromagnetic interference that the electronic device may cause. The EMC filter 204 can pass the filtered power to a pre-regulator 206. The pre-regulator 206 can regulate the voltage of the filtered power. The output of the pre-regulator 206 can pass the regulated power to a main DC/DC converter or main power DC/DC converter 208 and/or to an auxiliary DC/DC converter or auxiliary power DC/DC converter 210. The auxiliary DC/DC converter 210 and an auxiliary power supply 212 can provide housekeeping service during power up, initialization and normal operation. The main DC/DC converter 208 can convert the regulated power from the pre-regulator 206 from a first voltage to a second voltage, different from the first voltage. The output of the DC/DC converter 208 can flow through a filter which can comprise an inductor 214 and capacitor 216. The filter can reduce noise from the voltage of the output of the DC/DC converter 208. The filtered output can flow to an Oring-FET 104. When the Oring-FET 104 is powered and operating properly, the Oring-FET 104 can serve as a low loss diode to pass voltage to the system bus 108. When the Oring-FET 104 is powered and operating properly, the Oring-FET 104 can assist and/or prevent current passing through the Oring-FET 104 from the system bus 108. An Oring-FET controller 106 can control the Oring-FET 104 when the Oring-FET 104 is operating properly.
Problems with such N+1 power supply configurations can arise if an Oring-FET 104 is faulty during power up. Typically, each power supply configuration 200 is powered up one at a time. When one or more power supply configurations 200 are providing power to the system bus 108, if a power supply configuration 200 being powered up has a faulty Oring-FET 104, the Oring-FET 104 would be shorted and current from the communicatively coupled system bus 108 can pass to the uncharged capacitor 216 due to the capacitor 216 no longer being isolated from the system bus 108. This can be referred to as an overcurrent. The overcurrent can cause a low voltage or sagging voltage on the system bus 106 which can cause the electronic equipment to enter an undesirable system reboot. In the event, that the power supply configuration 200 has a faulty Oring-FET 104, the faulty Oring-FET 104 can continue to cause the electronic equipment to enter system reboots when powered up.